Lipases are enzymes naturally produced by a wide variety of living organisms from microbes to higher eukaryotes. Fatty acids undergoing oxidation in tissues of higher animals must be in free form (that is, non-esterified) before they can undergo activation and oxidation. Thus, intracellular lipases function to hydrolyze the triacylglycerols to yield free fatty acids and glycerol. Enzymes useful in the present invention will be referred to as "lipases", but include enzymes described as being a "hydrolase" or "cutinase", as well as a "lipase", because the useful enzymes form hydrolysis by-products from oil substrates. All three terms and enzymes are contemplated and included by the use of the term "lipase" herein.
Bacterial lipases are classically defined as glycerolesterhydrolases (EC 3.1.1.3) since they are polypeptides capable of cleaving ester bonds. They have a high affinity for interfaces, a characteristic which separates them from other enzymes such as proteases and esterases.
Cutinases are esterases that catalyze the hydrolysis of cutin. For example, cutinase allows fungi to penetrate through the cutin barrier into the host plant during the initial stages of a fungal infection. The primary structures of several cutinases have been compared and shown to be strongly conserved. Ettinger, Biochemistry. 26, pp. 7883-7892 (1987). Sebastian et al., Arch. Biochem. Biophys., 263 (1), pp. 77-85 (1988) have recently found production of cutinase to be induced by cutin in a fluorescent P. putida strain. This cutinase catalyzed hydrolysis of p-nitrophenyl esters of C.sub.4 -C.sub.16 fatty acids.
Because of this ability, lipases have long been considered as potential components in detergent compositions, and lipases obtained from certain Pseudomonas or Chromobacter microorganisms have been disclosed as useful in detergent compositions: Thom et al., U.S. Pat. No. 4,707, 291, issued Nov. 17, 1987 and Wiersema et al., European Patent Application 253,487, published Jan. 20, 1988. However, although lipases hydrolyze oil in solutions simulating laundry wash compositions, they have not proven to be very effective in removing oil stains from fabrics.
PCT application WO 88/09367 suggests the use of one of the lipases employed in the present invention in laundry applications. However, the method of use suggested merely comprises conventional use in laundry solutions or cleaning compositions. This lipase, so used by conventional methods, is no more effective than other lipases in removing oil stains from fabrics. Therefore, a need remains for effective utilization for the potential of lipases for removing oil stains in laundry applications.
Fabric treatments with non-enzyme compounds are known to alter the properties of fabric surfaces. For example, paralleling the development of durable-press and wash/wear fabrics, has been work on imparting oil and water repellency to fabrics. A widely used treatment utilizes a fluorochemical (sold by Minnesota Mining and Manufacturing Company under the mark Scotchgard) and another composition used for such fabric treatment is sold by E.I. du Pont de Nemours & Co. under the trademark Zepel. But oil and water repellant treated fabric have posed difficulties in removing stains by laundering, due to the fact that these repellant treatments make the fabric hydrophobic, and the oils forced onto such fabrics (particularly clothing at collar and cuffs) therefore are difficult to remove. One approach to this problem has been to treat the fabrics with soil release polymers. However, a need remains for imparting improved oil stain removal properties to surfaces, and particularly to fabrics exposed to significant oil staining, such as table cloths, aprons and clothing at body contact points such as collars and cuffs.
The use of lipases and/or cutinases in imparting oil hydrolysis activity during storage or wear has not been previously recognized.
When soil is released from fabric during laundering there is a further problem of redeposition of the oily soil on the previously cleaned fabric. This problem is well recognized. U.S. Pat. No. 4,909,962, issued Mar. 20, 1990, inventor Clark, attributes the redeposition of oily soil, in part, to phase separation (at least in the case of a pre-spotting composition when diluted with water in the wash bath). U.S. Pat. No. 4,919,854, issued Apr. 24, 1990, inventors Vogt et al., discloses detergent and cleaning preparations which include redeposition inhibitors described as water-soluble, generally organic, colloids (e.g. polymeric carboxylic acids and gelatin).